Complex versatile control logic units based on micro-processors or micro-controllers allow electrical appliances to be equipped with a plurality of functions which aim to enhance the operating comfort of the appliance but which as a result of their diversity, are perceived by many users more as confusing than as facilitating handling.
If each possible function is allocated its own button, this rapidly results in a complex diversity of buttons on the appliance so that a user must first search for the corresponding button to activate a desired function. This is not very convenient and is also expensive because of the large number of buttons.
The alternative is to allow the selection of a desired function by successive actuation of several buttons. The number of buttons required is thereby reduced but this can easily become confusing for a user since not every combination of button actuations results in a meaningful result and there can be intermediate states in which the control logic unit expects the actuation of certain buttons to be able to adjust a function and possibly ignores other button actuations.
In electrical appliances it is also usual to use operating elements with an allocated status display. In the simplest case, this can be a mains switch with a built-in light, for example, which is switched on when the appliance is operating and which is switched off when it is not operating or conversely. Such a status display makes it easy for a user to identify an adjusted operating state on an electrical appliance but in no way simplifies the adjustment of a desired operating state.